diff --git a/robust/mult_uncertainty.m b/robust/mult_uncertainty.m
index 83e5e67..4494af3 100644
--- a/robust/mult_uncertainty.m
+++ b/robust/mult_uncertainty.m
@@ -27,8 +27,21 @@ data = frd(info.Bounds(:, 2), w);
 % use a second-order model
 I_m_analytic = tf(fitmagfrd(data, 2));
 
+% For MIMO systems, the division in the expression for I_m doesn't make
+% sense
+% This is another way to compute it:
+opt = wcOptions('MussvOptions','m3'); % for better lower bound
+[wcg, wcu, info_num] = wcgain(G-G_nom, w);
+[wcg, wcu, info_den] = wcgain(G_nom, w, opt);
+
+resp_im = info_num.Bounds(:, 2) ./ info_den.Bounds(:, 1);
+
+data_2 = frd(resp_im, w);
+I_m_analytic_2 = tf(fitmagfrd(data_2, 2));
+
 sigma(I_m, w); hold;
 semilogx(w, 20*log10(info.Bounds(:, 2)), 'green');
 sigma(I_m_analytic, 'red');
+sigma(I_m_analytic_2, 'yellow');
 
 I_m_analytic